Geology and geophysics of the southern Raft River Valley geothermal area, Idaho, USA

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The Raft River valley, near the boundary of the Snake River plain with the Basin and Range province, is a north-trending late Cenozoic downwarp bounded by faults on the west, south, and east. Pleistocene alluvium and Miocene-Pliocene tuffaceous sediments, conglomerate, and felsic volcanic rocks aggregate 2 km in thickness. Large gravity, magnetic, and total field resistivity highs probably indicate a buried igneous mass that is too old to serve as a heat source. Differing seismic velocities relate to known or inferred structures and to a suspected shallow zone of warm water. Resistivity anomalies reflect differences of both composition and degree of alteration of Cenozoic rocks. Resistivity soundings show a 2 to 5 ohm·m unit with a thickness of 1 km beneath a large part of the valley, and the unit may indicate partly hot water and partly clayey sediments. Observed self-potential anomalies are believed to indicate zones where warm water rises toward the surface. Boiling wells at Bridge, Idaho are near the intersection of north-northeast normal faults which have moved as recently as the late (?) Pleistocene, and an east-northeast structure, probably a right-lateral fault. Deep circulation of ground water in this region of relatively high heat flow and upwelling along faults is the probable cause of the thermal anomaly.

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Publication type Conference Paper
Publication Subtype Conference Paper
Title Geology and geophysics of the southern Raft River Valley geothermal area, Idaho, USA
Volume 2
Year Published 1976
Language English
Publisher U.S. Energy Research and Development Administration
Publisher location Washington, D.C.
Contributing office(s) Energy Resources Program
Description 10 p.
Larger Work Type Book
Larger Work Subtype Conference publication
Larger Work Title Proceedings: second United Nations Symposium on the development and use of geothermal resources, San Francisco, California, USA, 20-29 May 1975
First page 1273
Last page 1282
Country United States
State Idaho
Other Geospatial Raft River Valley
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